A new vaginal
microbicide gel and drug formulation looks promising for empowering
women in developing countries to protect themselves from HIV during
intercourse, without having to inform their partners, according to
research published in the April 2011 issue of the journal Antimicrobial Agents and Chemotherapy.

HIV infection remains a
major risk for women in sub-Saharan Africa and Southeast Asia, and one
over which women often have little control due to unequal gender status
over much of those regions. Investigators say the gel, the subject of
the current research, will be cost-effective for such women, and
laboratory studies suggest the gel-drug combination will be safe and
effective. ImQuest BioSciences, Inc., the drug’s developer, hopes to
have the gel-drug combination in human clinical trials in 2012.

One of the drug’s most
important attributes is that it has two distinct mechanisms of action.
IQP-0528, as the drug is known, inhibits the virus’ ability to enter
human cells, as well as the reverse transcription of the virus’ genome
into the host genome, “which is required for productive infection of
the cell,” says Robert Buckheit, of ImQuest BioSciences, of Frederick,
MD. In that sense, IQP-0528 is like two drugs in one. Laboratory
studies suggest that the product will work very effectively.

The investigators
assayed a number of candidate drugs before choosing IQP-0528. Some of
the other drugs were chemically unstable, or unstable at pH values to
which they would be exposed, or otherwise unstable, says corresponding
author Patrick F. Kiser of the University of Utah, Salt Lake City. It
was critical for the formulation to be stable at ambient temperatures
of sub-Saharan Africa, as refrigeration is not widely available in much
of that region.

ImQuest continues to
investigate a variety of options for drug, gel, and device
formulations. “At present we have gels, intravaginal ring, and biofilm
formulations of IQP-0528, in addition to the gel described in the
paper, and products developed, which include combinations of IQP-0528
with tenofovir, which was recently found to inhibit the sexual
transmission of HIV,” says Buckheit. All this is in the interest of
developing a product which women can use most easily and comfortably.

Kiser is particularly
proud of the “symphony of tools and techniques used in the study. We
had virology, human explant studies, chemical and physical stability
studies, transport studies, and permeability studies of the drug,” he
says. “Putting all those things together is not trivial.”